If a -1309 error appears during an attempt to copy a large file to a disk which is in the FAT32 or MS-DOS format in Mac OS X, it is caused by limitations of the FAT32 format; specifically, this format cannot accomodate files larger than 4GB regardless of how much space is available on the drive.
This issue can be dealt with in several ways:- Open the Disk Utility in the /Applications/Utilities/ folder and use that to reformat the whole disk in the Mac OS Extended or Mac OS Extended (Journaled) formats after transferring the data on it to another drive temporarily. This option is the best when the drive doesn't need to be used with a PC.
- Follow the instructions in this document to create both Mac OS Extended and FAT32 partitions on that drive. This is useful when the drive needs to be used with a PC, but the file does not. Before this is done, copy everything currently on that drive to another location.
- Use an application such as MacHacha to segment the large file. This method makes the file accessible to someone on a PC.
